Firearms generally utilize a pair of front and rear sights mounted on a portion of the firearm, such as the slide of a semiautomatic firearm, which assist in aiming the firearm. The rear sight is essentially a notched pedestal having a trapezoidal shape which fits into a trapezoidal dovetail in the firearm. The front sight generally consists of a sight bead projecting upwardly which is aligned with the notch in the rear sight for aiming.
Conventional fixed sights, as described above, are suitable for most applications where extreme accuracy is not required. Even though firearms are machined with great accuracy, manufacturing tolerances nevertheless introduce some degree of inaccuracy so that the actual trajectory of the bullet does not coincide with the sight axis. Attempts have been made to correct this limitation and to compensate for wind effects by designing adjustable sights. Adjustable sights have also been designed to compensate for the effect of wind on the bullet's trajectory, to vary the aiming point depending upon the target's distance, and to vary the aiming point to compensate for variations in performance resulting from the use of different types of ammunition. All of these adjustable sights are relatively expensive, and they are somewhat fragile. Additionally, they are generally used with specially manufactured firearms and are thus not suitable for a wide retrofit market.